Describe, with the aid of a sketch, the operation of a gear pump.
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What is a gear pump?
A gear pump is a type of positive displacement pump that uses the meshing of gears to move fluids. It works by trapping fluid between the gear teeth and the pump casing and then carrying it around to the discharge side, where the meshing gears force the fluid out.
1. Useful information on Gear Pumps – Michael-Smith-Engineers.co.uk
2. 2.972 How A Gear Pump Works – MIT
Key Characteristics:
- Positive Displacement: Delivers a fixed volume of fluid per revolution, regardless of the discharge pressure. 1. Useful information on External Gear Pumps – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
- Self-Priming: Can handle air and create a vacuum, eliminating the need for manual priming. 1. Useful information on External Gear Pumps – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
- High-Viscosity Fluids: Handles thick and viscous fluids efficiently, including oils, resins, and even some pastes. 1. Useful information on Gear Pumps – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
- Simple Design: Relatively simple construction with few moving parts, making them reliable and easy to maintain. 1. Useful information on Gear Pumps – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
- Compact: Occupies a small footprint, suitable for installations with limited space. 1. Gear Pump – Top Supplier & Dealer in Dubai, UAE www.pokharamotors.com
Types of Gear Pumps:
- External Gear Pump:
- Two external spur gears mesh together within the casing. 1. Gear pump – Wikipedia en.wikipedia.org
- Fluid is carried between the gear teeth and the casing. 1. Useful information on External Gear Pumps – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
- Internal Gear Pump:
- An external gear meshes with an internal gear (with teeth facing inward) within the casing. 1. Gear pump – Wikipedia en.wikipedia.org
- Fluid is carried in the spaces between the gear teeth and the crescent-shaped space between the gears.
Working Principle:
- Suction: As the gears rotate, they unmesh at the inlet side, creating expanding spaces between the gear teeth and the casing. This creates a partial vacuum, drawing fluid into the pump. 1. Useful information on Gear Pumps – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
- Trapping: The fluid is trapped between the gear teeth and the casing as the gears continue to rotate. 1. What is a Gear Pump: A Comprehensive Guide – heash technique bv www.heash-tech.com
- Transport: The meshing gears carry the trapped fluid around the casing towards the outlet. 1. Useful information on Gear Pumps – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
- Discharge: At the outlet side, the meshing of the gears forces the fluid out of the spaces and into the discharge pipe. 1. Useful information on External Gear Pumps – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
Advantages:
- High Pressure Capability: Can generate high pressures, making them suitable for hydraulic systems and applications requiring forceful fluid transfer. 1. What You Need To Know About Gear Pumps – FCX Performance news.fcxperformance.com
- Self-Priming: Can handle air and create a vacuum, simplifying operation and eliminating priming concerns. 1. Internal and External Gear Pump Guide & Design – Castle Pumps www.castlepumps.com
- Handles Viscous Fluids: The close tolerances and positive displacement action make them excellent for pumping thick and viscous fluids. 1. Verdergear – Accurate Gear Pumps – Verder Liquids www.verderliquids.com
- Compact and Efficient: They have a high power density, delivering significant flow rates for their size.
- Reliable and Durable: Simple design with few moving parts leads to reliable operation and long service life. 1. Gear Pumps, The Internal and External of it all. – Kelair Pumps Australia kelairpumps.com.au
Disadvantages:
- Pulsating Flow: The flow from a gear pump is pulsating due to the meshing and unmeshing of the gears. Pulsation dampers may be required in some applications to smooth out the flow.
- Wear and Tear: Close tolerances between the gears and casing can lead to wear, especially when handling abrasive fluids. Regular maintenance and replacement of wear parts are essential. 1. Useful information on pumping abrasive liquid – Michael Smith Engineers www.michael-smith-engineers.co.uk2. Tips for Maintaining and Troubleshooting A Series Gear Pumps: Best Practices for Ensuring Longevity and Reliability roperpumps.com
- Not Suitable for Shear-Sensitive Fluids: The meshing action of the gears can cause shear forces, making them unsuitable for delicate or shear-sensitive fluids.
Applications:
- Hydraulic Systems: Powering hydraulic machinery and equipment.
- Lubrication Systems: Delivering lubricating oil to engines and machinery.
- Fuel Transfer: Transferring various fuels, including diesel and heavy fuel oil.
- Chemical Processing: Handling a wide range of chemicals, including viscous and corrosive fluids. 1. Gear pumps: versatility in fluid handling – Chemical Industry Journal www.chemicalindustryjournal.co.uk
- Food and Beverage Industry: Pumping edible oils, syrups, and other food products. 1. Understanding Gear Pumps: Working Principles, Applications, and Benefits www.knowledge-sourcing.com
Overall, gear pumps are a versatile and reliable choice for various applications where positive displacement, self-priming capability, and the ability to handle viscous fluids are required.
What are the main components of a gear pump?
The main components of a gear pump typically include:
- Gears:
- The heart of the pump, usually a pair of meshing gears. 1. Gear Pump Selection Guide – Aurora Pro Scientific www.auroraprosci.com
- Can be external gears (meshing on their outer diameters) or internal gears (one gear inside the other). 1. Useful information on Gear Pumps – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
- Typically made of hardened steel or other wear-resistant materials. 1. Gear Pump Selection Guide – Aurora Pro Scientific www.auroraprosci.com
- Casing (or Housing):
- The outer shell encloses the gears and provides structural support.
- Contains the inlet and outlet ports for fluid flow. 1. External Gear Pumps: Functions and Definitions – heash technique bv www.heash-tech.com
- Made of cast iron, ductile iron, steel, or aluminum, depending on the application.
- Drive Shaft:
- One of the gears is connected to the drive shaft, which transmits rotational power from the motor or prime mover.
- Made of hardened steel or other suitable materials.
- Bearings:
- Support and guide the rotating shafts of the gears, reducing friction and ensuring smooth operation. 1. Gearboxes – WD Bearings wdbearings.com
- Typically ball bearings or roller bearings.
- Shaft Seals:
- Prevent leakage of fluid from the pump along the drive shaft. 1. Useful information on pump shaft seals – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
- Can be mechanical seals, lip seals, or other types depending on the fluid and application. 1. Useful information on pump shaft seals – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
- End Plates:
- Seal the ends of the pump casing and provide support for the bearings and shaft.
- May contain ports for pressure relief valves or other accessories.
- Inlet and Outlet Ports:
- Openings in the casing for fluid to enter and exit. 1. Gear Pump Explained – saVRee www.savree.com
Additional Components (Depending on Design & Application):
- Pressure Relief Valve: Protects the pump and system from overpressure by releasing excess fluid.
- Wear Plates: May be installed in areas of high wear to protect the casing and gears.
- Bushings: In internal gear pumps, a bushing supports the idler gear (the non-driven gear). 1. Useful information on Gear Pumps – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
Remember:
Gear pumps often have close tolerances between the gears and casing, making them sensitive to debris and wear. Regular maintenance and proper filtration are important to ensure their longevity and performance. 1. Useful information on Gear Pumps – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
The specific design and materials used may vary based on the type of gear pump (external or internal) and the intended application.
How does a gear pump operate?
Gear pumps operate on a simple but effective principle, utilizing the meshing of gears to create a positive displacement action that moves fluid from the inlet to the outlet.
1. Useful information on External Gear Pumps – Michael-Smith-Engineers.co.uk
Let’s break down the operation in detail, considering both external and internal gear pump designs:
External Gear Pump Operation:
- Suction (Intake):
- The two external gears rotate in opposite directions. 1. Couple Rotational Motion with Gears – MATLAB & Simulink – MathWorks América Latina la.mathworks.com
- As the gear teeth disengage on the inlet side, they create expanding spaces or voids between the teeth and the pump casing. 1. Useful information on Gear Pumps – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
- This creates a partial vacuum, drawing fluid into the pump through the inlet port. 1. Useful information on Gear Pumps – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
- Trapping & Transport:
- The fluid gets trapped in the spaces between the gear teeth and the casing wall. 1. Useful information on Gear Pumps – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
- As the gears continue to rotate, they carry these “pockets” of fluid around the outer periphery of the casing, away from the inlet and towards the outlet. 1. Useful information on Gear Pumps – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
- The close meshing of the gears and the tight clearances between the gears and the casing prevent the fluid from leaking back to the inlet side. 1. Useful information on Gear Pumps – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
- Compression & Discharge:
- On the outlet side, the gear teeth mesh back together. 1. Hydraulic Gear Pump – Eurobalt eurobalt.net
- This progressively reduces the volume of the spaces between the teeth, compressing the trapped fluid. 1. Useful information on Gear Pumps – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
- The increased pressure forces the fluid out of the pump through the outlet port. 1. Useful information on Gear Pumps – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
Internal Gear Pump Operation:
- Suction (Intake):
- An external gear (the “power” gear) drives an internal gear (with teeth facing inward) within the casing.
- As the gears rotate, the space between the gear teeth and the crescent-shaped space between the two gears expands on the inlet side.
- This expansion creates a partial vacuum, drawing fluid into the pump.
- Trapping & Transport:
- The fluid is trapped in the spaces between the gear teeth and the crescent-shaped area as the gears rotate. 1. Gear Pump Explained – saVRee www.savree.com
- A crescent-shaped seal separates the inlet and outlet sides, preventing backflow. 1. How does a gear pump work? – YouTube m.youtube.com
- The rotating gears carry the trapped fluid around the casing to the outlet. 1. Useful information on Gear Pumps – Michael-Smith-Engineers.co.uk www.michael-smith-engineers.co.uk
- Discharge:
- At the outlet side, the meshing of the gears forces the fluid out of the spaces and into the discharge pipe. 1. 3 Secrets You Don’t Know About Gear Pumps – HARSLE www.harsle.com
Key Features of Gear Pump Operation
- Positive Displacement: The meshing gears create sealed chambers that trap and transport a fixed volume of fluid with each rotation. 1. Gear Pump Selection Guide – Aurora Pro Scientific www.auroraprosci.com
- Self-Priming: The ability to create a vacuum at the inlet allows the pump to draw fluid in, even if there’s initially air in the lines.
- Continuous Flow: Although there’s some inherent pulsation due to the gear meshing, the flow is relatively continuous compared to reciprocating pumps.
- High-Viscosity Fluids: The close tolerances and positive displacement action make them suitable for pumping viscous fluids. 1. Verdergear – Accurate Gear Pumps – Verder Liquids www.verderliquids.com
- Reversible: Most gear pumps can operate in either direction, allowing for bi-directional flow if needed. 1. It Flows Both Ways: a guide to running an internal gear pump in reverse – Viking Pump www.vikingpump.com
In summary: Gear pumps utilize the meshing of gears to create a positive displacement action that moves fluid from the inlet to the outlet. Their simplicity, reliability, self-priming capability, and ability to handle viscous fluids make them valuable in various industrial and marine applications.
1. Useful information on Gear Pumps – Michael-Smith-Engineers.co.uk